Tool having a rotating processing unit

ABSTRACT

A tool with a rotating processing unit with tool elements, preferably an abrading or polishing tool, and with a motor including a drive shaft for driving the processing unit is provided. The drive shaft is drivingly connected with a drive plate disposed at right angles to the drive shaft and provided with first connecting device releasably interacting with corresponding second connecting device which are connected with a base plate for the processing unit. The processing unit will thus be driven by the engagement of the first and second connecting device. The tool elements are fixed in the base plate. By this design it is possible for a user to replace the processing unit rapidly and in a simple way without needing to replace the individual tool elements.

FIELD OF THE INVENTION

The present invention concerns a tool with rotating processing unit withtool elements, preferably an abrading or polishing tool, and with amotor including a drive shaft for driving the processing unit, whereinthe drive shaft is drivingly connected with a drive plate disposed atright angles to the drive shaft. The tool is preferably a handheld tool.However, the invention may as well be applied to a stationary tool.

BACKGROUND OF THE INVENTION

The area of the invention is within tools for abrading and polishing andtherefore provided with tool elements in the form of abrasive elements.However, the invention may also be used with other processing units,such as e.g. buff wheels.

Rotating abrasive or polishing tools provided with abrasive elements areknown. Such tools are used extensively in the woodworking industry andwithin the metalworking industry. Similarly, the tools can be usedwithin industries for working other materials, as e.g. glass fibreconstructions.

By surface treatment, as e.g. sanding or polishing, of various items, itis known to use abrading and polishing members which are mounted on aprocessing unit in the form of an abrading/grinding head. Such anabrading head can be disc-shaped wherein the abrasive elements aremounted on a side face of the disc or built up as combination ofdisc-shaped and cylindrical parts. However, it is typical of theseabrading heads that they are provided with a kind of dovetail grooves inwhich a number of abrasive and/or brush members are mounted. Thesemembers may include abrasive elements in the form of abrasive paper,brushes of fibre, hair, steel or other metals and combinations of these,e.g. in the form of retainer brushes supporting the abrasive paperduring use. The abrasive paper can e.g. be sandpaper for buffing wood,metal and the like, cloth and/or fabric for polishing, or leather.Brushes, support brushes and/or retainer brushes may e.g. be steelbrushes, plastic brushes or other types of brushes.

In the following, these members are designated by a common term as toolelements.

Such tool elements can be made of a plastic material in which abrasivepaper and brushes are embedded by moulding a plastic member aroundabrasive paper and brush. Alternatively, brushes and/or abrasive papercan be fixed in a metal rail by squeezing the latter around the brushesand/or the abrasive paper of which the tool member in question is to bemade, or in other suitable ways.

On a typical abrading head are arranged as an average between 8 and 50tool elements which are to be replaced regularly by industrial use. Sucha replacement typically occurs by pulling them out of the dovetailgrooves in which they are seated and replacing them with new toolelements.

The drawback of the different types of abrading heads, and for thatmatter also of the different types of tool elements for use in theseabrading heads, is that the different tool elements do not fit all typesof abrading heads.

Therefore, it is often necessary to acquire many different types ofabrading heads and/or tool elements in order to perform different tasks,obviously entailing increased use of time for changing a tool or amachine on which the abrading head is applied, as well as a greaterinvestment in abrading heads.

In particular when grinding profiled work pieces in the wood industry,it is important to have a rotating processing head with variable speedwhich can be used in connection with various forms of processing headsfor abrading, trimming and polishing.

From industrial works, preferably in the wood industry, abrading toolsare known having variable speed and in the form of pneumatic tools withabrading heads mounted thereon. It is also known with hand tools withabrading heads driven by an electric motor with variable speed.

In spite of a long-standing need for hand tool which can also be used bydo-it-yourself users who need rapid and simple replacement of theprocessing unit in order to have various tool elements available fordifferent processing operation, such a hand tool with a processing unitwhich is easy to replace and which is intended for abrading, trimmingand polishing has not previously existed.

An apparatus of the type mentioned in the introduction is known from US2008171495. This tool comprises a drive plate where tool elements aremounted in a replaceable way. However, this does not solve the problemof easy replacement and change between different types of tool elementsby replacing the entire processing unit.

Thus there is an unsatisfied demand for a hand tool which can be used bythe professional user as well as the do-it-yourself user, and whereinstead of replacing the abrading tool the entire processing unit isreplaced.

By making the processing tool as a disposable unit which is replacedwhen worn, there is a need for a construction which is more reasonablypriced than the hitherto known, wherein the holder for abrading tools ofthe processing unit is made by milling grooves in the holder, which e.g.can be a cup head or a drum. This is particularly significant to handtools for the do-it-yourself user.

OBJECT OF THE INVENTION

It is the object of the present invention to indicate a tool in whichdifferent types of tool elements are mounted on different processingunits, and where the processing units are easy to replace in order tochange between different processing units and in order to replace theunit by wear. Furthermore, it is an object to indicate a processing unitwhich is suited for disposable use by being a cheap design.

DESCRIPTION OF THE INVENTION

According to the present invention, this object is achieved by a tool ofthe kind mentioned in the introduction which is peculiar in that thedrive plate is provided with first connecting means releasablyinteracting with corresponding second connecting means which areconnected with a base plate for the processing unit such that theprocessing unit is driven by engagement of the first and second means,and that the tool elements are fixedly mounted in the base plate.

By establishing the interacting connection means on the base plate ofthe processing unit and the drive plate of the drive shaft, a suitablechoice of connecting means can be performed so that they can be releasedquickly. Suitable choices will typically be Velcro connections andbayonet connections which can readily be engaged or disengaged. The usercan hereby readily replace the processing unit.

The processing unit can be replaced by a corresponding processing unitin case of wear or by another type of processing unit when differenttasks are to be performed in continuation of each other. The drive shaftis usually a rigid shaft but it is also possible that the drive shaft ofthe tool is a flexible shaft.

By the tool according to the invention it is thus possible for a user toapply the same motor unit to different processing units which can bereplaced without using tools in a simple way. The motor unit can be apneumatic motor with variable speed or an electric motor. An electricmotor can also have variable speed.

The tool elements will be fixedly mounted in the base plate of theprocessing unit. It is therefore not intended that individual toolelements are to be replaced as is the case with prior art tools. Thusthere is no need that a do-it-yourself user has to keep track of thevarious tool elements for the tool. When the tool elements are worn, theuser can simply replace the processing unit. In other words, it can besaid that the invention operates with disposable processing units.

By using a tool according to the invention with rapid mounting anddismounting of the processing unit, it is possible in a tool to use aplurality of processing units which are mutually replaced, depending onthe processes to be performed. The various processing units fit into thetool as modular elements.

According to a further embodiment, the tool according to the presentinvention is peculiar in that the base plate of the processing units inthe form of top plate, bottom plate and spacer housing are made bycasting. As opposed to the machined parts of prior art processing units,this will enable a cheap construction. The production costs can herebybe reduced to a level that makes the processing units suited fordisposable use.

According to a further embodiment, the tool according to the inventionis peculiar in that first and second connecting means are selected amongVelcro connections and bayonet connections.

The applied first and second connecting means are to have a design suchthat they can transmit the torque required for using the tool. If abayonet socket is used, the engagement of the bayonet will be adaptedsuch that by rotation in the peripheral direction of the tool there isestablished a locking engagement in the bayonet socket.

If using Velcro connections, by the present-day Velcro connections itwill be possible to transmit torques with a magnitude as applied byrotary hand tools.

In that connection it is remarked that the tools can typically beexpected to be hand tools with a motor capacity in the magnitude up toabout 3500 W.

As mentioned above, Velcro connections and bayonet connections will bevery simple as tools are not required when mounting and dismounting aprocessing unit from the drive plate of the tool.

According to a further embodiment, the tool according to the inventionis peculiar in that the drive plate and the processing unit are enclosedby a housing which is fixed in relation to the motor and which isprovided with a connection for exhausting material removed by the use ofthe tool elements of the processing unit, as the drive plate and theprocessing unit are provided with openings for passage of the material.

As the tools are typically used for abrading or trimming tasks, it isessential that the dust formed by abrasion/trimming can be removed in asafe way. Therefore it is preferred that the processing unit is enclosedby a housing such that only the tool elements are exposed. In the baseplate of the processing unit, openings are provided between the toolelements. These openings communicate with corresponding openings in thedrive plate. Dust can hereby be sucked into the housing through theseopenings and be remove via the exhaust connection.

Moreover, the surrounding housing will constitute a safeguard as therotating periphery of the processing unit is not exposed. The risk ofinjury is reduced thereby.

According to a further embodiment, the tool according to the presentinvention is peculiar in that that the tool elements of the processingunit includes means for abrading, trimming, polishing, or similar tasks.

As mentioned above, a tool according to the present invention willprimarily find application for abrading and polishing tasks. The toolelements will therefore be means for abrading, trimming, polishing, orsimilar tasks. Such tool elements can be chosen with a design which isknown per se from the previously mentioned industrial machines withreplaceable tool elements.

According to a further embodiment, the tool according to the presentinvention is peculiar in that the base plate of the processing unit is acircular disc rotating about a central axis and having a surface towhich edge parts of a number of pieces of abrasive paper, which are slitinwardly against the surface, are fitted orientated largelyperpendicularly out from the surface. The pieces of abrasive paper arepreferably disposed radially.

As an alternative to an orientation largely at right angles to thesurface, the tool elements can be disposed at an angle which deviatefrom right angles relative to the surface. Also, it will be possible todispose the tool elements with an orientation which is not completelyradial but at an angle to a radial orientation.

By an inclining mounting of the tool elements it is possible to changethe processing properties of the tool.

By such a construction there is established an abrasive member where theuse of slit abrasive paper pieces is particularly suited for abradingprofiled surfaces. The slit abrasive paper pieces on the face of acircular disc are known per se from previous apparatuses wherereplaceable tool elements are used.

According to a further embodiment, the tool according to the presentinvention is peculiar by also including support brushes supporting thepieces of abrasive paper as the pieces of abrasive paper and the supportbrushes are secured in a common foot piece which is mounted in the baseplate of the processing unit.

The application of support brushes provides a particularly efficientabrading action.

According to a further embodiment, the tool according to the presentinvention is peculiar in that the pieces of abrasive paper and thesupport brushes are mounted in foot pieces, that the base plate includesa bottom plate and a top plate provided with mounting apertures for thefoot pieces, that the foot pieces ore oversized at their bottomscompared with the mounting apertures such that the foot pieces aresecured in the mounting apertures when joining the bottom plate and thetop plate. The mounting apertures are formed as openings that surroundthe foot pieces.

By using foot pieces which at their bottom are oversized in relation tomounting apertures in the top plate it is possible to insert theindividual tool elements from the back side of the top plate. Afterinsertion of the tool elements in the apertures, the bottom plate andthe top plate are joined with the bottom of the foot pieces locatedbetween the top plate and the bottom plate. The bottom plate will herebypress the foot pieces into secure engagement in the mounting apertures.Bottom plate and top plate can be interconnected in various known ways,e.g. by gluing, welding or by mechanical clamping.

The tool elements will then project from the top side of the top plateof the base plate. The connecting means are disposed at the side of thebottom plate of the base plate facing the drive plate of the driveshaft.

According to a further embodiment, the tool according to the presentinvention is peculiar in that the processing unit includes a circulardisc or wheel rotating about a central axis and having a surface uponwhich is mounted a disc-shaped piece of abrasive paper.

The processing unit will preferably include a circular disc.Alternatively, discs with an edged or other shape can be used. Theapplied disc will rotate about a central axis. A rotationally symmetrictool is hereby achieved. On the circular disc there is a plane surfaceupon which there can be fitted a disc-shaped abrasive paper piece,alternatively a polishing means.

By using the tool there will thus be abrading with a plane tool unit.The tool element can be mounted on a soft and yielding base for adaptingto various surface contours when abrading.

According to a further embodiment, the tool according to the inventionis peculiar in that the processing unit and the drive plate are alignedfor rotation about a common central axis.

By a common central axis for processing unit and drive plate there isachieved a simple design of the abrading tool, and there is no risk ofadverse effects occurring by shaking and vibrations, as known e.g. fromeccentric grinders.

According to a further embodiment, the tool according to the inventionis peculiar by including several processing units adapted for mutualsubstitution for application to different processing operations. Eachprocessing unit has second connecting means that interact releasablywith the first connecting means.

Now is given an explanation in detail of special tool elements in theform of slit abrasive paper for use in the tool.

The lamellae of the abrasive element are formed by cutting an abrasivepaper transversely of its longitudinal direction so that strips orlamellae appear which at one end are interconnected by means of anunbroken strip of abrasive paper secured to the U-shaped profile. Thefree end thus consists of a number of parallel lamellae of abrasivepaper extending largely at right angles to the longitudinal direction ofthe profile. In a plane parallel with the abrasive lamellae, supportbrushes will be disposed in immediate vicinity of the lamellae such thatthey support the lamellae by grinding.

The abrasive or polishing effect is obtained as a result of the actionof the lamellae as they sweep a work piece during rotation of the tool.The support brushes, as indicated by the word, have a function ofsupporting the abrasive lamellae. However, the support brushes can alsobe produced from a material such that they contribute to the abrasive orpolishing effect. The support brushes are placed right behind theabrasive paper pieces so that they support the abrasive paper pieces andthereby hold the abrasive part of the abrasive paper pieces against thesurface to be abraded.

Furthermore, the support brushes provide that the abrasive paper itemswill never bend around the foot and lie back across the surface of theabrading wheel. It is an advantage that there is a certain distance fromthe surface of the abrading wheel and down to the surface to be abradedsuch that abraded material can be conveyed away and for reducing therisk of the surface of the abrading wheel coming into contact with theabraded surface.

The number of rows of support brushes may be different, depending on howmuch support the abrasive paper pieces are to have. This entails thate.g. there may be three rows of support brushes behind each individualabrasive paper piece.

By the abrasive paper pieces being mounted mainly perpendicularly on thesurface of the wheel, it is possible to utilise the abrasive part of theabrasive paper pieces better than in the case with abrasive paper piecesthat are placed intentionally with large overlaps. An abrading wheelaccording to the present invention has thus a longer service life thanthe commonly known flat or annular grinding wheels.

With an interspace between the abrasive paper pieces is furthermoreachieved a better grinding effect as the interspaces contribute totransport abraded material away from the abrasive paper pieces, wherebythe abrasive parts of the abrasive paper pieces are provided a betterabrasive effect because they are not filled up with abraded material.Also, exhaust of abraded material from the interspaces can easily beeffected.

Instead of mounting the abrasive paper pieces so that they have a radialextension over the greater part of the radius of the surface, theabrasive paper pieces can be mounted in relation to the direction ofrotation in a rearwards curved arrangement.

As it appears from the above explanation, a tool according to theinvention can be regarded as a modular tool where individual modulesused in the processing units can be reused with various tool elements.This makes the tool suited for do-it-yourself users who only need amotor unit in order to have a number of different processing unitsavailable.

Change between individual processing units is easily performed due tothe releasable connecting means. For example, a user who is about totrim a surface with a processing unit with abrasive lamellae willencounter an area with large irregularities or burrs that are difficultto remove with a trimming unit. The user can then readily change thetrimming unit with a plane grinding unit and remove the irregularities,and then mount the trimming unit in the tool again. This reduces theneed for the number of tools which are to be available for the user.

DESCRIPTION OF THE DRAWING

In the following, the invention will be explained in more detail withreference to the enclosed drawing wherein:

FIG. 1 shows an exploded view of a tool according to the invention,illustrated with three interchangeable processing units;

FIG. 2 shows different views of a first of the processing units in FIG.1 in the form of an abrading head with abrasive strips mounted at rightangles to the base plate of the processing unit and with radialorientation;

FIG. 3 shows different views of a top plate for the base plate shown inFIG. 2;

FIG. 4 shows different views of a bottom plate for the base plate shownin FIG. 2;

FIG. 5 shows different views of a second of the processing units shownin FIG. 1 in the form of an abrading head with abrasive strips mountedobliquely to the base plate of the processing unit and with a non-radialorientation;

FIG. 6 shows different views of a top plate for the base plate shown inFIG. 5;

FIG. 7 shows different views of a bottom plate for the base plate shownin FIG. 5;

FIG. 8 shows different views of a third of the processing units in FIG.1 in the form of a grinding wheel with a face at which a disc-shapedabrasive paper is mounted;

FIG. 9 shows a various views of a housing for the tool shown in FIG. 1;

FIG. 10 shows a various views of a drive plate for the tool shown inFIG. 1;

FIG. 11 shows connecting means in the form of a Velcro male part for thetool shown in FIG. 1;

FIG. 12 shows connecting means in the form of a Velcro female part forthe tool shown in FIG. 1; and

FIG. 13 shows different views of connecting means in the form of abayonet connection shown together with a processing unit correspondingto the one shown in FIG. 5.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In the different figures on the drawings identical or correspondingelements will be indicated with the same reference number and a specificexplanation to each single figure will therefore not be given.

In FIG. 1 is shown a tool 1, including a motor 2 with a drive shaft 3, ahousing 4, a drive plate 5 and three different processing units 6, 7 and8. The motor 2 is a pneumatic motor with three handles 9 and aconnection 9′ for connecting air in one of the handles.

FIG. 2 shows details of the first processing unit 6. It includes a baseplate 10 formed by a top plate 11 and an interacting bottom plate 12.There are eight radially oriented mounting apertures 13 for receivingeight tool elements in the form of abrasive elements 14, and eightexhaust openings 15 provided there between. Each abrasive element 14includes a foot piece 16 in the form of a plastic strip in which isembedded slit abrasive paper pieces 17 as well as support brushes 18.Exhaust openings 24 aligned with the exhaust openings 15 are formed inthe bottom plate 12.

The foot pieces 16 are designed with increased thickness such that theyhave a bottom 19 which is wider than their top 20. Hereby, they can bemounted in the mounting openings 13 from a back side 21 of the top plate11 such that the abrasive paper pieces 17 project from the front side 22of the top plate 11, disposed largely at right angles to the front side22 as the foot pieces 16 are welded to perpendicularly collared edgeparts 23 on the mounting apertures 13. The bottom plate 12 is glued onthe top plate 11 such that there is formed a jointed base plate 10 withfixed abrasive elements 14.

The top plate 11 is shown in several views in FIG. 3, and the bottomplate 12 is shown in several views in FIG. 4.

The processing unit 6 is provided with a glued Velcro female part 25which at its peripheral edge 26 has finger-like cutouts 27 thatfacilitate separation from a corresponding Velcro male part 28 (see FIG.11) which is glued on the drive plate 5. The Velcro female part 25 andthe Velcro male part 28 have aligned exhaust openings 29 and 30,respectively.

FIG. 5 shows a second processing unit 7 differing from the one shown inFIG. 2 in that the abrasive elements 14 are mounted in the top plate 11′in mounting openings 13′ which are non-radially oriented and haveobliquely collared edge parts 23′ for receiving the abrasive elements 14at an angle of 60° relative to the front side 22. In the bottom plate12′, opposite each abrasive element 14, there are a series of outwardlybent extensions 31 supporting the bottom 20 of the foot piece 16 inorder to ensure the oblique orientation.

The top plate 11′ is shown in several views in FIG. 6, and the bottomplate 12′ is shown in several views in FIG. 7.

FIG. 8 shows a second processing unit 8. This processing unit is asurface grinder and includes a cylindrical spacer housing 32 on which isglued a Velcro female part (not shown in FIG. 8) intended forinteraction with a Velcro male part 28 which is glued to the drive plate(not shown in FIG. 8). Exhaust openings 36 are formed in the spacerhousing 32. On the spacer housing 32 is mounted an elastic intermediatepiece 33 with finger-like cutouts 34 and exhaust openings 35. On theintermediate piece 33 is glued a Velcro female part 25 which interactswith a Velcro male part (not shown in FIG. 8) glued to a round,disc-shaped abrasive paper piece 46 provided with exhaust openings 35.All exhaust openings are aligned.

FIG. 9 shows the housing 4 for surrounding the drive plate 5 and aprocessing unit 6, 7 or 8. The housing includes a bottom 37 with anexhaust connection 38 intended for connecting with an exhaust system(not shown). The housing 4 furthermore includes a mounting ring 39 foruse when fastening the housing on the motor 2. The housing includes acylindrical ring 40 constituting a cylindrical jacket on the housing. Abrush ring 41 is fitted on the cylindrical ring. The brush ring 41 canbe made with different heights, e.g. 5 mm, 10 mm and 15 mm, such that itwill contribute to defining the pressure which will be exerted byabrasive elements in the housing 4 on a base.

FIG. 10 shows the drive plate 5. The drive plate 5 is formed by a plate42 and a Velcro male part 28. These two parts are glued together. Bymeans of lock nut 43, the drive plate 5 is screwed on a hub 44 which ismounted on the drive shaft 3 of the motor. The plate 42 is provided withexhaust openings 45 that are aligned with the exhaust openings 29 on theVelcro male part 28.

FIG. 11 and FIG. 12 show the Velcro male part 28 and the Velcro femalepart 25, respectively.

FIG. 13 shows the first and second connecting means in the form of abayonet connection 47, 48 which include collared flanges 47 spaced alongthe periphery of an annular wall 49 rising at right angles from adisc-shaped plate 50 along the periphery 51 of the latter such that abowl-shaped drive plate 5′ is formed. The drive plate 5 is provided withexhaust openings 45.

The bayonet connection 47, 48 furthermore includes projecting flanges 48which are distributed along the peripheral edge 52 of a circular baseplate 11″, which between the flanges 48 have notches 53 distributedalong the peripheral edge so that the base plate 11″ can be placedwithin the bowl-shaped drive plate 5′ when the notches 53 are alignedwith the collared flanges 47. The base plate 11 can then be rotated suchthat the projecting flanges 48 are brought to engage under the collaredflanges 47.

The bayonet connection is shown on a processing unit corresponding tothe one shown in FIG. 5, with mounting apertures 13″ for abrasiveelements 14 and with exhaust openings 15. However, corresponding bayonetconnections can be provided in connection with the other two types ofprocessing units such that rapid replacement and change betweendifferent processing units are possible.

1. A tool with rotating processing unit with tool elements, preferablyan abrading or polishing tool, and with a motor including a drive shaftfor driving the processing unit, wherein the drive shaft is drivinglyconnected with a drive plate disposed at right angles to the driveshaft, wherein the drive plate is provided with first connecting meansreleasably interacting with corresponding second connecting means whichare connected with a base plate for the processing unit such that theprocessing unit is driven by engagement of the first and second means,and that the tool elements are fixedly mounted in the base plate.
 2. Thetool according to claim 1, wherein the first and second connecting meansare chosen among hook and loop connections and bayonet connections. 3.The tool according to claim 1 wherein the drive plate and the processingunit are enclosed by a housing which is fixed in relation to the motorand which is provided with a connection for exhausting material removedby the use of the tool elements of the processing unit, as the driveplate and the processing unit are provided with openings for passage ofthe material.
 4. The tool according to claim 1, wherein the toolelements of the processing unit include means for abrading, trimming,polishing, or similar tasks.
 5. The tool according to claim 1, whereinthe base plate of the processing unit is a circular disc rotating abouta central axis and having a surface to which edge parts of a number ofpieces of abrasive paper, which are slit inwardly against the surface,are fitted orientated largely perpendicularly out from the surface. 6.The tool according to claim 5, wherein support brushes supporting thepieces of abrasive paper as the pieces of abrasive paper and the supportbrushes are secured in a common foot which is mounted in the base plateof the processing unit.
 7. The tool according to claim 5 wherein thepieces of abrasive paper and the support brushes are mounted in footpieces, that the base plate includes a bottom plate and a top plateprovided with mounting apertures for the foot pieces, that the footpieces are oversized at their bottoms compared with the mountingapertures such that the foot pieces are secured in the mountingapertures when joining the bottom plate and the top plate.
 8. The toolaccording to claim 1, wherein the processing unit includes a circulardisc rotating about a central axis and having a surface upon which ismounted a disc-shaped piece of abrasive paper.
 9. The tool accordingclaim 1, wherein the processing unit and the drive plate are aligned forrotation about a common central axis.
 10. The tool according to claim 1,wherein several processing units are adapted for mutual substitution forapplication to different processing operations.
 11. The tool accordingto claim 1, wherein the base plate of the processing unit is made bycasting.